Electrode clamp and support



Dec. 1, 1942. w. E. MOORE 2,303,392

ELECTRODE CLAMP AND 'SUPPORT Filed March 16, 1940 2 Sheets-Sheet .l

w. E. MOORE ELECTRODE CLAMP AND SUPPORT Dec. 1,1942.

2 Sheets-Sheet 2 Filed March 16, 1940 g I a W? WillimEMOOre PatentedDec. 1, 1942 UNITED STATES P TENT OFFICE ELECTRODE CLAMP AND SUPPORTWilliam Enoch Moore, Pittsburgh, Pa., assignor to Delaware EngineeringCorporation, Wilmington, Del.

Claims.

My invention relates to improvements in electric arc furnaces, and moreparticularly to electrode supporting and operating mechanism therefor.

An important object of the present invention is to provide an electrodesupporting mechanism which will provide a large electrical contactsurface to engage the electrode.

Another object of the invention is the provision of an electrodesupporting structure which is effectively cooled to prevent overheatingof all of its parts.

A further object of the invention is to provide an electrode clampingmechanism which will securely hold the electrode against slipping andwhich will not adhere to the electrode through burning or the like.

Still another object of the invention is the provision of an electrodesupporting mechanism which is of simple and inexpensive construction andwhich is efiicient and durable in use.

Other objects and advantages of the invention will be apparent duringthe course of the following description.

In the accompanying drawings, which form a part of this specificationand wherein the numerals designate the parts throughout,

Figure 1 is a top plan view of an electrode supporting structureembodying this invention,

Figure 2 is a side elevation thereof,

Figure 3 is an end elevation of the electrode clamp, looking from theelectrode arm toward the contact end of the clamp,

Figure 4 is a top plan view of the clamp ring,

Figure 5 is a sectional view therethrough taken on the line 5--5 ofFigure 4,

Figure 6 is a sectional view on the line 6-6 of Figure 4,

Figure 7 is a top plan view of the clamping wedge,

Figure 8 is a rear elevation thereof, and,

Figure 9 is a detail longitudinal sectional view through the wedge guideand support. 1

In the drawings, wherein for the purpose of illustration is shown apreferred embodiment of the invention, the numeral it designates anelectrode adapted to extend through the roof of an electric arc furnace.Electrodes of this type are supported from electrode columns disposed atone side of the furnace, and are moved vertically on the column when astationary column is employed or move vertically with the column when arise fall type of electrode column is employed. A suitable horizontalarm is connected at one end to the electrode column and is provided atits other end with a clamp to engage the electrode. The presentinvention is directed to the construction and operation of thiselectrode clamp and arm.

In Figures 1 and 2 of the drawings, the invention is shown forillustration as applied to the stationary type of electrode column II onwhich a cross-head structure I2 is slidably mounted for verticalmovement. Suitable rollers l3 are carried by the cross-head to engagethe column, and these rollers are preferably adjustable toward and awayfrom the column. A split, hollow clamping sleeve I4 is carried by thecrosshead I2 and is preferably formed integrally therewith. A tubularelectrode arm l6 telescopes at one end with the clamping sleeve l4 andis adjustably secured therein by means of clamping bolts ii. A suitablelayer of insulation material i8 is disposed between the clamping sleeveI4 and the tubular arm Hi to completely insulate the electrode arm 16from the clamping sleeve [4, cross-head l2 and column II. The end of thearm 56 adjacent electrode IE1 is closed by a metal plate I9 whichextends beyond the sides of arm 56 to form a flange to which theelectrode clamp may be bolted. The other end of arm 16 is also closed topermit the circulation of a cooling fluid through the hollow arm. Theelectrode clamp body 29 is bolted to the flange formed by plate 19, bymeans of suitable bolts 2|. A contact shoe 22 is bolted between themachined contact end of the electrode clamp 20 and electrode arm I6,extending thereabove and being provided with bosses 23 above theelectrode arm for connection to the ends of bus pipes 24. The bus pipes24 are extended back around the cross-head l2, passing through andbeyond suitable insulated clamps 25 carried by a bracket 26 on the rearof cross-head l2. Suitable flexible water tubes 21 and flexibleelectrical conductors 28 are connected to the ends of the bus pipes 24behind the clamps 25. v

A fluid tube 29, which may be flexible if desired, connects the interiorof the hollow electrode arm with one of the bus pipes 24 so that acooling medium such as water may be circulated through the arm to coolthe clamp, contact shoe 22, arm l6 and insulation [8. It will be notedthat the insulation l8, in addition to being water cooled, is disposedat a substantial distance from the heat adjacent the electrode. Asuitable pipe 30 connects the electrode clamp with the other bus pipe 24while another pipe 3| connects the electrode clamp with the hollow armIt. It will be seen that a cooling medium is circulated through the buspipes, hollow arm and clamp.

The body or electrode contact shoe 2B of the electrode clamp is of highelectrical conductivity material such as copper and extends through anarc of substantially 145. lhe body of the clamp is extended vertically asubstantial distance above and below the electrode arm as seen in Figure2 to provide a large contact area to engage the electrode. A flameshield 32 comprising a yoke shaped strap of heat resisting steel orother suitable material having relatively higher electrical resistance,is joined at its ends to the opposite sides of the clamp body completesthe circle of the electrode clamp. The vertical Width of the shield 32is about one-half that of the clamp body 23.

Cooling coils 33 are of steel cast into the body 23 of the clamp andextending throughout the circle formed by the shield 32, being securedto the inner wall of the shield 32. A steel wedge receiving channel orwedge guide 33 is secured to the coils and flame shield by welding orthe like at a point diametrically opposite the center of the body of theclamp. The side edges 34 of the channel 33 are turned up to provide atrough to receive and guide the wedge, as seen in Figures 4, 6 and 9,while a lip 35 is bent over the top of coils 33 and shield 32. The coils33 and shield 32 have their upper portions extended out beyond theirlower portions adjacent the wedge channel 23' to produce a downwardtaper for accommodating the wedge.

The electrode wedge comprises an arcuate body portion 36 wider at itstop than at its bottom and having its electrode engaging surfaceprovided with upwardly extending ratchet teeth 3'! to dig into thesurface of the electrode so that the wedge will firmly engage theelectrode and be tightened by any downward pull of the electrode. Awedge rib 38 is formed on the back of the wedge body 36 and tapers fromtop to bottom to engage the wedge channel 33' and force the grooved faceof the wedge into firm wedging engagement with the electrode 10.extension 33 is formed at the top of the wedge, extending rearwardlytherefrom. A hook flange or finger 40 depends from the rearward edge ofextension 39. When the wedge is dropped into the channel 33, as when theelectrode is removed, the hook finger 40 drops on the outside of shield32 to hold the wedge and prevent its falling into the furnace.

The rear surface of the wedge rib 38 is provided with two adjacentvertical rows of notches 4|, 5;

the notches of each row being staggered, to be engaged by a lever orpinch bar 42 shown on Figure 5 for prying up and removing the wedge. Thenotches 4| are staggered to provide a close spacing thereof.

By reference to Figures 1 and 4 it will be seen that the coils 33 andshield 32 are spaced from the electrode which is engaged only by theclamp body 20 and wedge 36. The wedge forces the electrode into firmengagement with the conducting clamp body. Due to this firm engagementand the extensive contact surface of the high conductive clamp body, agood electrical contact is produced. The high conductivity clamp bodyconducts the current to the electrode while the relatively higherresistance of the steel shield, coils and wedge limits the amount ofcurrent carried by the wedge. This high resistance of the wedge carryingportion of the clamp ring avoids the tendency of the electrode to burnto the wedge or the A horizontal wedge to the wedge channel, adisadvantage found in the usual wedge clamps.

The ring formed by the coils 33 and shield 32 is elongated as well astapered opposite the clamp body 20 to accommodate the wedge. Thecirculation of a cooling medium through the arm 16 and coils 33effectively cools the insulation [8, arm [6, contact shoe 22, clamp body20, flame shield 32, wedge channel 33 and the wedge 36. The groovedsurface of the Wedge prevents slipping of the electrode in the clampwhile the notches 4| permit easy removal of the wedge.

The clamp of the present invention is easily manufactured, is simply andrapidly operated, insures a good electrical contact without overheatingof any of its parts and the wedge will not burn to the electrode. Due tothe provision of the finger 43, the wedge cannot drop into the furnace.

While I have shown and described the preferred embodiment of theinvention, various changes in the size, shape and arrangement of partsmay be resorted to without departing from the spirit of my invention orthe scope of the subjoined claims.

Having thus described my invention, what I claim and desire to protectby Letters Patent is:

1. For use in an electric furnace having an electrode, an electrodeclamp and supporting mechanism comprising an arcuate clamp body of highelectrical conductivity material adapted to engage a portion of thecircumference of the electrode, a wedge guide disposed in spacedrelation to said clamp body, means connecting the wedge guide and clampbody, and a wedge slidably received in said wedge guide and adapted toengage a second portion of the circumference of the electrode and forceit into engagement with the clamp body, the wedge, Wedge guide andconnecting means havin a relatively higher electrical resistance thanthe clamp body to limit the amount of electric current carried by thewedge and a lower coefiicient of expansion.

2. For use in an electric furnace having an electrode, an electrodeclamp and supporting mechanism comprising an arcuate clamp body of highelectrical conductivity material adapted to engage a portion of thecircumference of the electrode, a wedge guide disposed in spacedrelation to said clamp body, means connecting the wedge guide and clampbody, a wedge slidably received in said wedge guide and adapted toengage a second portion of the circumference of the electrode and forceit into engagement with the clamp body, the wedge guide and connectingmeans having a relatively higher electrical resistance than the clampbody to limit the amount of electric current carried by the wedge, acooling pipe passing through the clamp body, and having surface contactwith the wedge guide and the connecting means, and means to circulate acooling medium through said pipe to cool the clamp body, wedge guide,connecting means and wedge.

3. For use in an electric furnace having an electrode, an electrodeclamp and supporting mechanism comprising an arcuate clamp body of highelectrical conductivity material adapted to engage the electrode, anannular cooling pipe coil having a portion of its length embedded insaid clamp body, said clamp body and cooling coil cooperating to form anelectrode receiving ring, a wedge guide carried by said cooling coil ata point diametrically opposite the clamp body, a wedge slidably receivedin said wedge guide and adapted to engage the electrode and force itinto "Wedge, wedge guide and cooling coil having a relatively higherelectrical resistance than the clamp body to limit the amount ofelectric current carried by the wedge, and means to conduct electriccurrent and a cooling fluid to said clamp body.

4. For use in an electric furnace having an electrode, an electrodeclamp and supporting mechanism comprising an arcuate clamp body of amaterial having high electrical conductivity and adapted to engage theelectrode, an annular cooling pipe coil having a portion of its lengthembedded in said clamp body, said clamp body and cooling coilcooperating to form an electrode receiving ring, a wedge guide carriedby said cooling coil at a point diametrically opposite the clamp body, awedge slidably received in said wedge guide and adapted to engage theelectrode and force it into intimate engagement with the clamp body, aflame shield secured to said clamp body and cooling coil; the wedge,cooling coil, flame shield and wedge guide having a relatively higherelectrical resistatnce than the clamp body to limit the amount ofcurrent carried by the wedge, means to conduct electric current to theclamp body, and means to circulate a cooling medium through the coolingcoil.

5. For use in an electric furnace having an electrode, an electrodeclamp and supporting mechanism comprising an arcuate clamp body of amaterial having high electrical conductivity and adapted to engage theelectrode, an annular cooling pipe coil having a portion of its lengthembedded in said clamp body, said clamp body and cooling coilcooperating to form an electrode receiving ring, a wedge guide carriedby said cooling coil at a point diametrically opposite the clamp body, awedge slidably received in said wedge guide and adapted to engage theelectrode and force it into intimate engagement with the clamp body, aflame shield secured to said clamp body and cooling coil; the wedge,cooling coil, flame shield and wedge guide having a relatively higherelectrical resistance than the clamp body to limit the amount of currentcarried by the wedge, means to conduct electric current to the clampbody, and means to circulate a cooling medium through the cooling coil,said clamp body being extended vertically a substantial distance aboveand below the cooling coil and flame shield to provide a large area tocontact the electrode.

6. For use in an electric furnace having an electrode, an electrodeclamp and supporting mechanism comprising an arcuate clamp body of highelectrical conductivity material adapted to engage the electrode, anannular cooling pipe coil having a portion of its length embedded insaid clamp body, said clamp body and cooling coil cooperating to form anelectrode receiving ring, a wedge guide carried by said cooling coil ata point diametrically opposite the clamp body, a wedge slidably receivedin said wedge guide and adapted to engage the electrode and force itinto intimate engagement with the clamp body; the Wedge, wedge guide andcooling coil having a relatively higher electrical resistance than theclamp body to limit the amount of electric current carried by the wedge,and means to conduct electric current and a cooling fluid to said clampbody, said wedge having a series of spaced notches on its rear surfaceto be engaged by a prying lever for removing the wedge,

and the electrode engaging surface of the wedge being provided withtransverse serrations.

7. For use in electric furnace having an electrode, an electrode clampand supporting mechanism comprising an arcuate clamp body of a materialhaving high electrical conductivity and adapted to engage the electrode,an annular cooling pipe coil having a portion of its length embedded insaid clamp body, said clamp body and cooling coil cooperating to form anelectrode receiving ring, a wedge guide carried by said cooling coil ata point diametrically opposite the clamp body, a wedge slidably receivedin said wedge guide and adapted to engage the electrode and force itinto intimate engagement with the clamp body, a flame shield secured tosaid clamp body and cooling coil; the wedge, cooling coil, flame shieldand wedge guide having a relatively higher electrical resistance thanthe clamp body to limit the amount of current carried by the wedge,means to conduct electric current to the clamp body, and means tocirculate a cooling medium through the cooling coil, said wedge having aseries of spaced notches on its rearward surface to be engaged by aprying lever for removing the wedge, and the electrode engaging surfaceof the wedge being provided with transverse serrations.

8. For use in an electric furnace having an electrode, an electrodeclamp comprising an arcuate clamp body, a wedge guide means con nectingsaid guide with said clamp body, a wedge slidably engaging said guideand extending thereabove, said guide, means, and wedge having a higherelectrical resistance than the clamp body, said Wedge being adapted toengage the electrode and force it against said clamp body, there beingtransverse upwardly extending ratchet teeth in the electrode engagingsurface of the wedge, and the opposite surface of said wedge beingprovided with a vertical series of spaced notches throughout asubstantial portion of its length adapted to be engaged by a pryinglever to remove the wedge from the guide.

9. For use in an electric furnace having an electrode, an electrodeclamp comprising a clamp body, a wedge guide operatively connected withsaid clamp body, a Wedge slidably engaging said guide and extendingthereabove, said wedge being adapted to engage the electrode and forceit against said clamp body, there being transverse serrations in theelectrode engaging surface of the wedge, and the opposite surface ofsaid wedge being provided with a vertical series of spaced notchesthroughout a substantial portion of its length adapted to be engaged bya prying lever to remove the Wedge from the guide, and a hook membercarried by and projecting beyond the upper portion of the Wedge andadapted to engage the guide and limit downward movement of the wedge inthe guide.

10. For use in an electric furnace having an electrode and an electrodesupporting column, the combination comprising an arcuate electrodecontact shoe having a cooling passage therein and a face conformed tothe curvature of the electrode, a yoke shaped shield comprising aseparate strap of metal having its ends secured to the opposite sides ofthe shoe, a wedge guide secured to the shield at a position opposite theshoe, an arcuate wedge having one side engaging the guide and anotherside for engaging the electrode, bus pipes connected to the contactshoe, said bus pipes being arranged one on each side of the column andprojecting beyond the column.

11. For use in an electric furnace having an electrode and an electrodesupporting column, the combination comprising an arcuate electrodecontact shoe having a cooling passage therein and a face conformed tothe curvature of the electrode, a yoke shaped shield comprising aseparate strap of metal having its ends secured to the opposite sides ofthe shoe, a wedge guide secured to the shield at a position opposite theshoe, an arcuate wedge having one side engaging the guide and anotherside for engaging the electrode, bus pipes connected to the contactshoe, said bus pipes being arranged one on each side of the column andprojecting beyond the column, said Wedge having ratchet teeth in theelectrode engaging side.

12. For use in an electric furnace having an electrode and an electrodesupporting column, the combination comprising an arcuate electrodecontact shoe having a cooling passage therein and a face conformed tothe curvature of the electrode, a yoke shaped shield comprising aseparate strap of metal having its ends secured to the opposite sides ofthe shoe, a wedge guide secured to the shield at a position opposite theshoe, an arcuate wedge having one side engaging the guide and anotherside for engaging the electrode, a tubular electrode arm for supportingthe shoe, a bus pipe connected to the tubular arm, a fluid passagebetween the arm and the cooling passage of the shoe, a second bus pipe,a fluid passage between the cooling passage of the shoe and the secondbus pipe, each of said bus pipes extending from the shoe, to a pointbeyond the column and passing on opposite sides of the column.

13.'An electrode support for an electric furnace electrode comprising anarcuate electrode contact shoe having a face curved to conform to thecurvature of the electrode, a yoke shaped shield comprising a separatestrap of metal of lower electrical conductivity than the shoe secured tothe opposite sides of the shoe, and forming with the shoe an electrodeencircling structure, an electrode guide secured to the shield oppositethe shoe, said guide having a downward and inwardly sloped face, and awedge having one side engaging the guide and another side for engagingthe electrode.

14. An electrode support for an electric furnace electrode comprising anarcuate electrode contact shoe having a face curved to conform to thecurvature of the electrode, a yoke shaped shield including a separatestrap of metal of lower electrical conductivity than the shoe secured tothe opposite sides of the shoe, and forming with the shoe an electrodeencircling structure, an electrode guide secured to the shield oppositethe shoe, said guide having a downward and inwardly sloped face, and awedge having one side engaging the guide and another side for engagingthe electrode, said wedge having ratchet like teeth on the electrodeengaging side.

15. An electrode support for an electric furnace electrode comprising anarcuate electrode contact shoe having a face curved to conform to thecurvature of the electrode, a yoke shaped shield including a separatestrap of metal of lower electrical conductivity than the shoe secured tothe opposite sides of the shoe, and forming with the shoe an electrodeencircling structure, an electrode guide secured to the shield oppositethe shoe, said guide having a downward and inwardly sloped face, and awedge having one side engaging the guide and another side for engagingthe electrode, said Wedge having ratchet like teeth on the electrodeengaging side, said guide, and wedge having relatively higher electricalresistance than the shoe.

WILLIAM ENOCH MOORE.

